This is my 1st L lense, Very happy with my purchase love thise lense, it is so crisp and clear from 100-400. All i hve to say is if you want the reach and the quality this is the lense to get, AWSOME lense. I almost bailed and got the sigma, 70-200 2.8. So glad I didnt. This is the lense to get if you want to do all around shooting wildlife, airplanes, cars, paning on this lense is great. IMO the best 1400 bucks ive spent.

I have a 20D and this was the first lense I picked up, i'm glad I did because this lense hasnt left the body. crisp clear pictures on full zoom, the Is is great. I can go on and on about this lense but the bottom line is if you want a lense that has a little bit of everything this is the lense to get.